Production of polyurethane foam, especially rigid foam for thermal insulation, involves processing a polyisocyanate-polyol reaction mixture in an extruder with an internal pressure above atmospheric pressure

摘要

Polyurethane foam is produced by processing the reaction mixture (polyisocyanates and compounds with at least two NCO-reactive hydrogen atoms) in an extruder in which the pressure is higher than atmospheric pressure. A method for the production of polyurethane foam by reacting polyisocyanates with compounds containing at least two hydrogen atoms which react with isocyanate groups involves (a) mixing these reactants, (b) feeding the mixture into an extruder in which the internal pressure is above atmospheric pressure, (c) extruding the foamed mixture and (d) hardening the foam. An Independent claim is also included for polyurethane foam, especially rigid polyurethane foam, obtained by this method.